Each type of data listed as a result of a SIMBAD interrogation is normally preceded by a header which provides a very short title to each listed parameter. This chapter explains the meaning of each of these titles.
Note: the character ~ in a field stands for no corresponding value (unknown value).
The following measurement types are presently included in SIMBAD:
| diameter | Stellar diameter |
| distance | Objects distance |
| ISO | Infrared Space Observatory (Observation Log) |
| IUE | International Ultraviolet Explorer (Observation Log) |
| MK | Stellar spectral classification in Morgan-Keenan system |
| PLX | Trigonometric parallaxes |
| pm | Proper motions (in 1950 equatorial frame) |
| ROT | Rotational velocities (V . sini) |
| V* | Data related to variable stars |
The next sections provide more details about each data type included in SIMBAD.
Example: diameter | diameterQ unit| error | filter | method | Reference | ---------------------------------------------------------------------------- diameter | 3.15E-05 mas |0.10E-05 |B |6A |2001A&A...367..521P| diameter | 3E-01 mas |0.10E-01 |V |3A |2001A&A...367..521P| diameter | 0.000345: mas |0.000012 |U |5A |2001A&A...367..521P| diameter | 7.00E+05: km |0.000012 |U |5A |2001A&A...367..521P|
| Header | Meaning |
| Diameter | Diameter value |
| Q | quality code (':' for uncertain) |
| unit | unit of the diameter (mas or km) |
| error | error on the diameter value |
| filter | filter or wavelength |
| method | determination method |
| reference | bibliographic reference |
Example:
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distance | distance Q unit | err- err+ | method | Reference |
------------------------------------------------------------------------
distance | 17.3 Mpc | -0.2 +0.6 |ST-L |2000A&A...356..849G|
distance | 125.43 kpc | -0.12 +1.20 |Cep |2000A&A...356..849G|
distance | 12.345 pc | -0.015 +0.040 |RRLyr |2008MNRAS.383..750C|
distance | 334 pc |-22 +25 |paral |2008MNRAS.383..750C|
| Header | Meaning |
| distance | Distance value |
| Q | quality code |
| unit | distance unit (pc, kpc, Mpc) |
| err- | minus error on the distance value |
| err+ | plus error on the distance value |
| method | determination method |
| reference | bibliographic reference |
Stellar parameters (Teff, log(g) and [Fe/H]) taken from the literature.
Example:
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Fe_h | Teff log.g|[Fe/H]*|CompStar |CatNo| Reference |
--------------------------------------------------------------
Fe_h | 5196 4.5 |-1.40 M|SUN |F4716|1991ApJS...77..515L|
Details of column meaning:
| Header | Meaning | ||||||||||
Teff | The effective temperature Teff, in °K | ||||||||||
log.g | The decimal logarithm of the surface gravity expressed in cm/s2 | ||||||||||
[Fe/H] | The metallicity index relative to the Sun,
in a log scale: [Fe/H] = log(Fe/H)* –log(Fe/H)(sun) A value of [Fe/H] = –1.0 therefore means a metal abundance 10 times lower than the Sun, and a value of [Fe/H] = +0.3 a metal abundance 2 times higher than the Sun. | ||||||||||
[Fe/H] flag (*) | is a flag on the [Fe/H] value which can take the
following values:
| ||||||||||
CompStar | designates the comparison star from which the [Fe/H] value was obtained. | ||||||||||
CatNo | identifies the star in the Cayrel et al. (1997A&AS..124..299C) compilation: it is made of the letter F or C for Field or Cluster star, followed by the ordinal record number in the Field star table (Table 1) or the Cluster star table (Table 2) | ||||||||||
Reference | Reference (bibcode) of the measurement |
Example:
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|Homogenized Name: ComplID |PROG |CL|D CAM IMAGE A| FES MD|Obs.date Time|ExpTim|m|CEB|S|Comments |F|Reference |
----------------------------------------------------------------------------------------------------------------------------------------
|HD 93308 :WE |NDEKD|61|L LWR 14605 L| BO|821112 001100|003000| |3X1|G|E=2X,C=110,B=30 |*|1996IUEML.C......0I|
| Header | Meaning | |||||||||||||||||||||||||||||||||||||||||||||
| Homogenized Name: ComplID | Homogenized target identifier, followed by a complement indicator for off-target spectra, or part of extended objects (e.g. SW for South-West) | |||||||||||||||||||||||||||||||||||||||||||||
| PROG | Observing Program Identification | |||||||||||||||||||||||||||||||||||||||||||||
| CL | Classification of IUE Target (see table of classes below) | |||||||||||||||||||||||||||||||||||||||||||||
| D CAM IMAGE A | Dispersion, Camera, Image, Aperture form the observation Identifier. | |||||||||||||||||||||||||||||||||||||||||||||
| Dispersion is Low or High | ||||||||||||||||||||||||||||||||||||||||||||||
| Camera is LWP, LWR, SWP or SWR for Long Wavelength Prime camera, Long Wavelength Redundant camera, Short Wavelength Prime camera and Short Wavelength Prime camera; | ||||||||||||||||||||||||||||||||||||||||||||||
| Image is the image number | ||||||||||||||||||||||||||||||||||||||||||||||
| Aperture is Large (10x20'') or Small (3'') | ||||||||||||||||||||||||||||||||||||||||||||||
| FES MD | is the count and mode. Photon counts are averaged over an integration time dependent on the needs of target acquisition; note that the FES detector saturates at a count of 28673 ! Mode is FU for fast track/Underlap, FO for fast track/Overlap, and SO for slow track/Overlap. | |||||||||||||||||||||||||||||||||||||||||||||
| Obs.date Time | Observation start | |||||||||||||||||||||||||||||||||||||||||||||
| ExpTim | Exposure time (s) | |||||||||||||||||||||||||||||||||||||||||||||
| m | Abnormality Code, as follows:
| |||||||||||||||||||||||||||||||||||||||||||||
| CEB | Exposure class made of 3 characters related to Continuum, Exposure,
Background with meaning:
| |||||||||||||||||||||||||||||||||||||||||||||
| S | Observation Station as Goddard or Vilspa | |||||||||||||||||||||||||||||||||||||||||||||
| Comments | Other comments related to the observation | |||||||||||||||||||||||||||||||||||||||||||||
| F | always *, spectrum accessible | |||||||||||||||||||||||||||||||||||||||||||||
| Reference | Reference (bibcode) of the measurement |
| List of IUE Classifications | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Example:
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MK |ds/mss Spectral type | reference |
---------------------------------------------------------------------
MK m| / G2Ibvar |1954ApJS....1..175B|
| Header | Meaning | ||||||||||||||||
| ds/mss | Brief description of the dispersive system used: | ||||||||||||||||
| |||||||||||||||||
| Spectral type | Spectral classification in the MK system | ||||||||||||||||
| reference | source of the spectral classification |
Example:
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PLX | plx :p.e| reference |
-------------------------------------
PLX | .005:004|1952$YUO.1952.....J|
| Header | Meaning |
| plx : p.e | Trigonometric parallax π (''), and probable error (in 10–3 arcsec) |
| reference | source of the parallax |
Example:
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PM | pm-ra [ m.e ]| pm-de [ m.e ]|Sys.| reference |
-------------------------------------------------------
PM | -.026[ .015]| +.025[ .012]|FK4 |1971$AGK3.C.......L|
| Header | Meaning |
| pm-ra [m.e.] | µα. cosδ in mas/yr, and σ within square bracket |
| pm-dec[m.e.] | µδ in mas/yr, and σ within square bracket |
| Sys. | Astrometric system used, which can be FK4, FK5 or ICRS |
| reference | source of the proper motions |
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ROT | Vsini [ err ] (mes)|Q| reference |
--------------------------------------------------
ROT | 9 [ ] ( 10)|E|1970CoKwa.189....0U|
ROT |<125.12 [10.10] ( )|A|1995ApJS...99..135A|
| Header | Meaning |
| Vsini | projected rotational velocity v sini (km/s) |
| [err] | error on the rotaional velocity |
| (mes) | number of measurements |
| Q | quality code (from A: best .. E: unknown origin) |
| reference | source of the rotational velocity |
Example:
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RVEL | Rvel (nmes)| rem |dis| reference |
-----------------------------------------------------
RVEL m| +5100 ( )| | |1973UGC...C.......N|
| Header | Meaning |
| Rvel (nmes) | radial velocity (km/s), and number of measurements |
| reference | bibliographic reference |
Example:
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V* |vartyp| Vmax p Vmin | period (d) | epoch (JD) |D/rt%|Reference |
-------------------------------------------------------------------------------------
V* m|Cd | 3.90 B 5.09 | 5.3663 | 2427628.86 |30.0 |1969$GCVS.C03.....K|
| Header | Meaning |
| Typ | Type of variability, summarized below |
| Max, p, min | Maximum and minimum of brightness; p specifies the type of magnitudes |
| P(d) | period (in days) |
| Ep(JD) | epoch (in Julian Days), which corresponds to: |
| |
| D/rt(%) | Duration of eclipse for Algol type stars; Raising time for all other variable types |
| Reference | source of data |
The classification defined in the 3rd Edition is:
| ACV | α2 CVn | IS | Rapid Irregular | |
| BCEP | β Cep | L | slow irregular | |
| BLLAC | BL Lac | LB | slow late-type irregular | |
| BY | BY Dra | M | Mira | |
| CEP | Long-period Cepheid | N | Nova | |
| CST | constant | NL | nova–like | |
| CW | W Vir | QSO | Quasar | |
| DCEP | δ Cep (Classical Cepheid) | RCB | R CrB | |
| DSCT | δ Sct | RR | RR Lyr | |
| E | Eclipsing binary | RRC | RR Lyr, P ≃0.3d | |
| EA | Algol-type eclipsing binary | RV | RV Tau (supergiants) | |
| EB | β Lyr–type eclipsing bin. | S | rapid variable | |
| ELL | ellipsoidal | SDOR | S Dor | |
| EW | W UMa–type eclipsing binary | SR | semi-regular | |
| GCAS | γ Cas | SN | Supernova | |
| I | Irregular | UG | U Gem | |
| IA | Irregular of early type | UV | UV Cet (flare) | |
| IN | Irregular in nebula | UVN | UV Cet in nebula | |
| INS | Rapid irregular in nebula | ZAND | Z And symbiotic star | |
| INT | T Tau irregular | ZCAM | Z Cam | |
| ZZC | ZZ Cet |